【摘要】 本文用DIG标记的cryI基因E.coRI-F片段的RNA探针,对鳞翅目高毒力菌株苏云金芽胞杆菌YBT-803质粒的BamHI/PstI酶解产物进行了Southern分析,将含有cryl基因的7.9kb和4.4kb的阳性片段与双功能载体pXI 61重组,转化感受态大肠杆菌TGl细胞,通过斑点杂交和快检获得分别含有7.9kb和4.4kb片段的克隆株,均可表达130kDa的杀虫晶体蛋白。从克隆中抽提重组质粒电转化到苏云金芽胞杆菌无晶体突变株Bti IPS·78/1l细胞中,可形成典型的菱形伴胞晶体。SDS-聚丙烯酰胺凝胶电泳表明,除了表达130kDa杀虫晶体蛋白外,还产生65kDa的多肽,它们对小菜蛾幼虫均有较高的毒力。更多还原

【Abstract】 Bacillus thuringiensis strain YBT-803 is highly toxic to plutella xylostella larvae. The fragment of plasmids digested wity Barn HI/PstI were analysed by southern blot using DIG-Labelled cryI gene E. coRF RNA probe. Both positive fragments of 7. 9 kh and 4. 4 kb were ligated to shuttle vector pXI 61 and transformed into competence cells E. coli TG1. The cloned strains harboring recombinant plasmids were obtained. It produced full-length 130kDa insectcidal crystal protein. The recombinant plasmid DNAs extracted from the cloned strains were transformed into acrystalloferous mutant Bti IPS·78/11 by electroporation. Two engineered strains with strong expression were obtained. They could form rhombus parasporal crystal and had higher toxic to plutella xylostella larvae than original strain. SDS-PAGE showed that molecular weith of insecticidal crystal proteins were 139 kDa and 65 kDa.更多还原